Lecture 9 - Integumentary System Flashcards

1
Q

membranes are composed of:

A

epithelium (epidermis), and connective tissues (dermis)

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2
Q

what are the 5 major components of the integumentary system (includes skin and accessory structures)

A
  • epidermis (skin)
  • dermis (skin)
  • exocrine glands (accessory)
  • hair (accessory)
  • nails (accessory)
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3
Q
  • largest organ system of the body (15% of total body mass)
  • ranges in thickness
  • most accessible system = best indicator of general health
  • responds directly to local influences
    these are all characteristics of:
A

skin

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4
Q

what are the five major functions of skin?

A

1) acts as a barrier: physical and immunological protection
2) thermoregulation
3) sensation: touch, pressure, vibration, temperature, pain
4) metabolic functions
5) social functions

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5
Q

what are the five layers of the epidermis?

A
  • stratum corneum
  • stratum lucidum
  • stratum granulosum
  • stratum spinosum
  • stratum basale (germinativum)
    (Come Lets Get Sun Burnt)
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6
Q

what is the basal layer of the epidermis?

A

the stratum germinativum

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7
Q

where are merkel cells and melanocytes found?

A

stratum germinivatum

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8
Q

stem cells in the stratum germinivatum constantly divide to give rise to new ______ to replace the dead ones that flake off

A

keratinocytes

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9
Q

the most abundant epithelial cells in the epidermis and synthesize keratin

A

keratinocytes

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10
Q

forms the basal lamina and ensures that the epithelium is firmly attached to the dermis

A

stratum germinativum

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11
Q

the least common cell type, but more abundant where skin has no hair

A

merkel (tactile) cells

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12
Q

what is the function of Merkel cells?

A

play an important role in touch sensation

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13
Q

what is the tactile (merkel) disc?

A

dermal sensory nerve fibre

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14
Q

makes up ~8% of epithelial cells - synthesizes melanin pigment

A

melanocytes

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15
Q

melanin granules are _____ by keratinocytes - form an “umbrella” over the nucleus to _____

A

phagocytized, protect DNA from UV radiation

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16
Q

what determines skin tone?

A

activity of granules produced and how they spread out in keratinocytes

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17
Q

what do melanocytes look like?

A

cells with long, slender processes

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18
Q

composed of several layers (8-10) of daughter living keratinocytes and Langerhans cells with protein filaments that attach keratinocytes together

A

stratum spinosum

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19
Q

what gives the stratum spinosum its spiny appearance?

A

adjecent cell junctions (provides strength)

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20
Q

a type of macrophage that originate from bone marrow and migrates to the epidermis

A

Langerhans (dendritic) cells

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21
Q

what is the role of Langerhan cells?

A

phagocytic capabilities and play and important role for immune response if pathogens penetrated the superficial layer

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22
Q

where are Langerhan cells found?

A

found in the oral cavity, esophagus, anal cavity, and vaginal canal

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23
Q

3-5 layers of mature keratinocytes which produce two types of granules, and is associated with a change in cell shape

A

stratum granulosum

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24
Q

what are kerahyalin granules?

A

granules produced by keratinocytes in the stratum granulosum which surrounds keratin (important for cornification)

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25
Q

what are lamellar granules?

A

water-resistant glycolipids produced by keratinocytes in the stratum granulosum which stick cells together (waterproofs the skin)

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26
Q

the accumulation of keratin from deep to superficial layers as cells mature

A

keratinization

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27
Q

at what layer in the epidermis do cells start to die?

A

stratum granulosum

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28
Q

how are calluses formed?

A

the accumulation of too many granules in the stratum granulosum due to abrasion

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29
Q

layer of the epidermis which is only present in volar/hairless skin (palmer and plantar skin)

A

stratum lucidum

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30
Q

the stratum lucidum has lots of ____ and thickened _____

A

keratin, plasma membranes

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31
Q

true or false: cells in the stratum lucidum retain their nucleus and organelles

A

false

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32
Q

contains multiple (20-30) layers of flattened, dead, interlocking keratinocytes which have no more organelles and are fully keratinized

A

stratum corneum

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33
Q

the most superficial layer of the epidermis

A

stratum corneum

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34
Q

what is dandruff?

A

clumps of dander stuck together with oil (sebum) from the scalp

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35
Q

what is the function of the stratum corneum?

A

protection against abrasion and microbial invasion

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36
Q

how long does it take epidermal cells to go from the stratum basale to the stratum corneum?

A

30-40 days

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37
Q

the interface between the dermis and epidermis

A

dermal papilla (dermis) and epidermal ridge (epidermis)

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38
Q

the peak and valley interface between the dermis and epidermis allows for:

A

a tight bond between the different layers of skin (resists shearing stresses)

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39
Q

in sensitive areas, such as the lips and genitials, the dermal papillae are tall, allowing ____ near the surface

A

nerve fibres and capillaries

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40
Q

the interface between the dermis and epidermis is very developed and unique to each individual in the:

A

fingertips

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41
Q

what are dermal papillae made of?

A

areolar connective tissue containing nerve endings, and many capillaries

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42
Q

what type of tissue is found in the reticular layer of the dermis?

A

dense irregular connective tissue

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43
Q

provides extensibility and elasticity to the skin, found in the reticular layer of the dermis

A

collagen bundles and elastic fibres

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44
Q

skeletal muscles of the face attach here for facial expressions

A

reticular layer of the dermis

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45
Q

collagen fibre bundles align along lines of _____ in the reticular layer of the dermis and form ______

A

tension, lines of cleavage

46
Q

what is the clinical significance of the lines of cleavage?

A

surgeons will try to cut parallel to the line of cleavage so wounds close and heal nicely

47
Q

cuts made perpendicular to the lines of cleavage can improperly heal and form large scars known as:

A

keloids

48
Q

what are stretch marks?

A

scarring due to internal damage of collagen bundles and stretching of vasculature

49
Q

stabilizes the position of skin relative to the underlying tissues

A

hypodermis

50
Q

a loose connective tissue that stores fat, pads the body, serves as an energy reservoir, and provides thermal insulation

A

hypodermis

51
Q

what are the three pigments responsible for skin tone?

A
  • melanin
  • hemoglobin
  • carotene
52
Q

what is melanin?

A

pigment from melanocytes in stratum basale

53
Q

what is the purpose of melanin?

A

protects from UV radiation

54
Q

what are freckles/moles?

A

accumulations of melanin/ outgrowth of melanocytes

55
Q

albinism is characterized by:

A

a lack of melanin

56
Q

produces the red pigment in dermal blood vessels

A

hemoglobin

57
Q

what is carotene?

A

a yellow/orange pigment in stratum corneum and hypodermis (precursor to vitamin A)

58
Q

true or false: skin tone can be diagnostic in conditions like cyanosis, erythema, jaundice, pallor, and hematoma

A

true

59
Q

first degree tissue damage to the skin affects the _____, causes mild pain, and _____

A

epidermis, erythema (skin redness)

60
Q

second degree tissue damage to the skin affects the _____, causes the formation of _____, edema, redness and pain

A

epidermis and some dermis, blisters

61
Q

third degree tissue damage to the skin affects _____, results in loss of _____, numbness due to _____, and granulation forms, skin grafting may be needed

A

epidermis, dermis, and hypodermis; function; loss of nerve endings

62
Q

what is the mechanism of secretion for merocrine glands?

A

normal exocytosis

63
Q

what is the mechanism of secretion for apocrine glands?

A

apical surface pinched off

64
Q

what is the mechanism of secretion for holocrine glands?

A

the entire cell is released

65
Q

what are the four types of exocrine cutaneous glands?

A

1) sweat glands
2) sebaceous glands
3) ceruminous glands
4) mammary glands

66
Q

what is the function of sweat glands?

A

secrete water and electrolytes

67
Q

what mechanism of secretion is used in sweat glands?

A

merocrine secretion and apocrine secretion

68
Q

what is the function of sebaceous glands?

A

secrete oily lipid (sebum) that coats hair and skin surface

69
Q

what mechanism of secretion is used in sebaceous glands?

A

holocrine secretion

70
Q

what is the function of ceruminous glands?

A

secretes earwax

71
Q

what mechanism of secretion is used in ceruminous glands?

A

apocrine secretion

72
Q

what is the function of mammary glands?

A

secretes breast milk

73
Q

what mechanism of secretion is used in mammary glands?

A

apocrine secretion

74
Q

found in the external ear canal - traps foreign particles, prevents entrance, reduces risk of bacterial and fungal functions

A

cerumen

75
Q

specialized for milk production to feed infant - regulated by interaction of sexual and pituitary hormones

A

mammary glands

76
Q
  • secretes regular sweat
  • widespread
  • tubes secrete directly onto skin surface
  • regulates body temp
  • controlled by the sympathetic nervous system
  • can also be released due to stress, fear, and embarrassment
    these are characteristics of:
A

merocrine sweat glands

77
Q
  • secretes odiferous sweat at puberty
  • specific to some body regions (axilla, groin, breast areola, facial hair)
  • duct opens into a hair follicle
  • strongly influenced by sexual hormones
  • stimulated during emotional stress and arousal
    these are characteristics of:
A

apocrine sweat glands

78
Q

inhibits bacterial growth - duct open onto hair follicle

A

sebum

79
Q

keeps hair and skin from becoming dry, brittle, and cracked

A

sebum

80
Q

secretions of sebaceous glands

A

sebum

81
Q

what is acne?

A

inflammation of sebaceous glands (from blockage of ducts and bacterial infection)

82
Q

at the onset of puberty, sebaceous glands increase in _____ and _____ increases in response to _____

A

size, secretions, sex hormones

83
Q

both hair and nails are composed of:

A

dead keratinized cells

84
Q

slender filament of keratinized cells that grow from a tube (follicle)

A

pilus (pili)

85
Q

where is hair found?

A

covers all body surfaces except for volar skin (hands and feet), lips, nipples, and parts of genitalia

86
Q

what are the four main functions of hair?

A
  • UV protection
  • thermal insulation for head
  • particle filtration for eyes and nose
  • touch sensation for most of body
87
Q

what are the three main parts of the hair follicle?

A
  • shaft
  • root
  • bulb
88
Q

part of the hair follicle that lies in the epidermis and above the skin

A

shaft

89
Q

part of the hair follicle that penetrates and anchors the hair to the dermis

A

root

90
Q

part of the hair follicle that lies deep in the dermis and allows for epithelial cells growth

A

bulb

91
Q

hair follicles have an _____ and _____ root sheath

A

epithelial, connective tissue

92
Q

smooth muscle from dermal collagen fibres (at the papillary layer of the dermis) to the root sheath (connects to sympathetic nervous system)

A

arrector pili

93
Q

what are the three types of hair?

A
  • lanugo (fine hair foetus to birth)
  • vellus (most hair on body)
  • terminal hair (longer, coarser, and pigmented)
94
Q

the texture of hair can be coarse or fine depending on:

A

the keratin content (genetically predetermined)

95
Q

hair colour is a result of:

A

synthesis of melanin by the melanocytes in the hair matrix

96
Q

the shape of the cross-section of a hair influences:

A

the curl of the hair

97
Q

part of the hair follicle that is made of densely packed elongated keratinized cells

A

cortex

98
Q

part of the hair follicle that is made of 2-3 layers of “soft” cells or irregular shape with prescence of air

A

medulla

99
Q

the matrix of the hair follicle

A

hair papilla

100
Q

part of the hair follicle that is made of single layer of scaly flat cells overlapping one another - coats the hair

A

cuticle

101
Q

what are the three stages of the hair growth cycle?

A
  • growth (active) stage
  • regression stage
  • resting stage
102
Q

what percent of hair is in the growth stage at any given time?

A

85%

103
Q

stem cells from hair matrix multiply and push existing cells superficially, these cells become keratinized and die (2-6 years in scalp)

A

growth (active) stage

104
Q

cells in the hair matrix stop dividing, preventing further growth - hair follicle atrophies (shrinks: 2-3 weeks)

A

regression stage

105
Q

metabolic activity is reduced, hair loses its anchorage and falls out after 3 months

A

resting stage

106
Q

what are finger nails?

A

clear scale-like modification of epidermis on distal, dorsal surface of fingers and toes

107
Q

grows 1mm per week from nail root

A

stratum basale - lunula

108
Q

cells are clear, solid, and visible at the nail body

A

stratum corneum

109
Q

forms the cuticle (band of epidermis)

A

stratum corneum

110
Q

part of the nail bed that serves to secure the nail

A

hyponychium